Do you initiate anticoagulation prophylaxis for pediatric patients with vascular compression secondary to solid tumor/lymphoma?

It is an interesting question, but lacks critical details. Of course, most cancers are prothrombotic, and anticoagulation can have risks:

• Is it arterial or venous compression? Complete obstruction? Acute or chronic? Collaterals?
• Is it compromising an organ?
• Is thrombus seen, or is there blood flow?...